JSIO URLs

The clever bit about JSIO is the placeholder URLs – i.e. the “jsio.gif#…” that goes in your image src attributes and background-image CSS properties. Everything after the “#” is the filename of the image that should be displayed. It doesn’t have to be the filename at all, it could just be a single letter or number or symbol or whatever. It doesn’t matter to JSIO. To JSIO, everything after the “#” is just a key into the resources object that holds data uri encoded images. As long as the key is unique (which it will be if you use filenames, since no two files in the same directory can have the same name), JSIO is happy.

Using filenames as keys into our resources object is beneficial to humans. Much more beneficial than coordinates in a sprite, simply because (hopefully) the filenames are meaningful; they describe the image. In comparison to sprites, the JSIO resources object also makes maintaining your image data much easier as it is trivial to add or remove images without having to move other images around within the sprite (and consequently all coordinates referencing your moved image).

Another benefit of using filenames as keys into the JSIO resources object is for fallback. If JSIO detects your browser is IE7 or lower, it’ll strip out “jsio.gif#” leaving just your image key as the image src, which is hopefully a valid URL to the original image. Also, if JSIO detects you’re running IE8 and the image data is larger than 32KB it’ll do the same thing*.

* …but not yet in v1.0.0 alpha

Since the image key is after the “#” (it is the URL “fragment”), your browser won’t send multiple requests for the 1*1px jsio.gif file – it’ll just send one request, cache the response, and use it again. By the way, the jsio.gif image is just a transparent 1*1px gif (for maximum efficiency), but it could be an “spinner” image or something, which is shown temporarily whilst the JSIO resources file is downloaded.

This post is about JSIO – JSIO is a tiny library that allows you to make fewer requests to your server by packaging all your site image data in a JavaScript file in data uri format. The official site for JSIO can be found here: jsio.freestyle-developments.co.uk. You can read more about why I started this project here.

9,726 thoughts on “JSIO URLs

  1. Анализ сделок за последние 3 года перед банкротством поможет выявить операции, которые могут быть оспорены в рамках процедуры банкротства. Переходите по запросу проверка последних сделок за три года. Проводим комплексную проверку договоров, переводов имущества, платежей и других сделок на предмет рисков признания недействительными. Подготовим профессиональное заключение и рекомендации для защиты ваших интересов. Конфиденциально, оперативно и с учетом актуальной судебной практики.

  2. Every weekend i used to go to see this web site, for the reason that i wish for enjoyment, for
    the reason that this this site conations in fact pleasant
    funny stuff too.

  3. My family always say that I am wasting my time here at net, however I know I am
    getting experience every day by reading
    such good articles or reviews.

  4. Magnificent items from you, man. I have take into account your stuff prior to and you are simply extremely fantastic.
    I actually like what you’ve got right here, really like
    what you’re saying and the way wherein you are saying it.

    You make it entertaining and you still care for to keep it smart.
    I cant wait to read far more from you. This is actually a
    tremendous website.

  5. Банкротство юридического лица — законный способ урегулировать долги и прекратить деятельность компании при невозможности исполнения обязательств. Переходите по запросу сколько длится процедура банкротства ООО. Поможем провести процедуру банкротства под ключ: от анализа ситуации и подготовки документов до сопровождения на всех этапах процесса. Защитим интересы бизнеса, минимизируем риски для руководителей и учредителей. Получите профессиональную консультацию уже сегодня.

  6. Pamiętaj o bezpiecznych metodach płatności i nigdy nie
    graj za pieniądze, których nie możesz stracić.Graj odpowiedzialnie.

  7. Does your website have a contact page? I’m having trouble locating it but, I’d like to send
    you an e-mail. I’ve got some recommendations for your blog you might be
    interested in hearing. Either way, great website and I look forward to seeing
    it expand over time.

  8. I am regular reader, how are you everybody? This article posted at this website is actually fastidious.

  9. Актуальное казино онлайн зеркало — сохраняет баланс.

    Авторизация по логину — без
    лишних полей.
    казино онлайн официальный
    с лицензией — входит в ТОП рейтингов.

    Сайт с зеркалами — провайдеры: NetEnt, Play’n GO.

    Официальный портал casino online — поддержка 24/7.

  10. Como recomendación probar antes de depositar plata propia, casi todos los proveedores cuentan con versiones demo gratis.
    Resulta lo más inteligente probar con la jugabilidad antes de arriesgar un peso.

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>